### Open Literature Review Summary

Chemical Name: Atrazine CAS No: 1912-24-9

ECOTOX Record Number and Citation: Lakshminarayana, l.S.S., 

### H.J. O'Neill, S.D. lonnavithula, D.A. Legerand, P.H. Milburn. 1992. Impact ofatrazine-bearing agricultural tile drainage discharge on planktonic drift ofanatural stream. Environ. Pollut. 76:201-210. 

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Purpose ofReview: Determine potential effects ofatrazine on an aquatic community. Endpoints from this study were also used to parameterizethe Comprehensive Aquatic System Model (CASM) and establish the model-associated LOC for atrazine.

Date ofReview: November 5, 2008
Purpose ofStudy: This study examines the potential effects ofatrazine agricultural runoffto aquatic plants and animals in a field stream.
Summary ofStudy Findings:

Methods: A field experimentwas performed at a study area in arural headwaterbasin, about48 km west ofMoncton, New Brunswick, Canada. The basin area (19 km2 

### in size) was mostly used for agriculture

- grain-based forage production andpasture, with some areas of silage com and othercrops. The main study area was afirst-order field stream flowing parallel to an 8ha subsurface tile drained field, which was divided into fourplots with drains placed at 0.8 m depth and 12 m apart (seeFigure 1; the setup including drainage system is further described in a 1989 Agriculture Canada reportbyMilburn, etal.). During the 1989 growing season, when the experimenttookplace, the field was cropped to silage corn. The four plots drained into individual outlet chambers housed in a covered building and fitted with flow measuring devices (devices not described). The four drains fell outside into a small 30 m long channel andwere carriedto the receiving stream that is the main object ofthe study. The receiving stream flowed into Salt Spring Brook, which ultimately flows to the Petitcodiac River. Eleven sampling locations were established: Sites 1-4 were the drain outlets from the four plots, Site 5 was the small 

# III1IIIIII 2087867

### channel containing the effluent from all plots combined, Sites 6-10 were onthe field stream (8 and 9, upstream ofthe confluence with the small channel containing the plots' runoff, were consideredbackground), and Site 11 was located on Salt Spring Brook about 2.5 km downstream from the confluence with the field stream. See Figure 1 for amap of sampling locations. Site 6 and 7 were separatedby a small earthen mound about 2 m wide, and during times ofincreased water flow were almostjoined due to water level rise (this was observed during a heavy precipitation event in November). See Table 1 

### and Table 2 for summaries ofthe sampling locations and meteorological monthly averages, respectively.

On June 6, 1989,justbefore the start ofthe study, atrazine (no information on product type) was applied at levels of4 Llha (not clearwhetherthis refers to dilute product or active ingredient; no description ofapplication method). No pre-application sampling occurred. 16.6 mm ofprecipitation occurred in the area between the time ofatrazine addition and sampling. Water and plankton drift samples were taken starting June 9 and ending on November 16, 1989, atroughly IS-day intervals. Samplings all occurred between 09:00 and 12:00. Water quality samples were collected in 1 Lplastic bottles and atrazine samples in I L amber glass bottles. Atrazine water samples were preserved to pH 9 within 3 hours ofcollection, and all water samples were stored at 4°C until analysis. Plankton drift was collected in two ways: first, sterilized 500 mL bottles were immersed beneath the surface and allowedto 

### till at hand depth (depth not quantified); and second, a 20 11 nitex plankton net scanned the contents oflarge (20 L) volumes ofwater. The plankton samples were fixed on site with 5% formaldehyde (for samples used to characterize flagellates, diatoms, and the cate dinoflagellates) and weakly alkaline Lugol's solution (for samples used in plankton enumeration). Plankton was counted using Utermohl's technique (American Public Health Association, 

### StandardMethods/or the Examination ofWaterand Wastewater, 1980) and the samples were studied using a two- orthree-step examination ofone chamber with an inverted microscope. The whole bottom areawas examined undera low magnification before high power objective examination, at lOx, 20x, and 40x with an eyepiece of 15x. Five to ten perpendicular stripes across the center and bottom coverglass were counted, keeping the width ofthe stripe constantby taking I to 5 whipple squares depending on the plankton density.

Water sample analysis was conductedby Environment Canada, Regional Water Quality Branch Laboratory in Moncton. Major ion and nutrient analysis followed the standards ofEnvironment Canada's Analytical Methods Manual 1979. Atrazine analyses were performedusing gas chromatography with anitrogen-phosphorus detector and 30-m megabore columns (DB-lorDB-17), afterXAD-4 resin column extraction, elution with ethyl acetate, andreduction ofethyl acetate over anhydrous sodium sulfate to 5 mL volume. When extraneous peaks were observed, columns were cleaned up with deactivated florisil. Confirmations wereperformed using a Hewlett-Packard gas chromatograph with a mass selective detector when concentrations permitted. A blind quality assurance/quality control program was employed using duplicate andtriplicate samples, lab and field spikes, and blanks. The laboratory's in-house QA/QC and

2participation in inter- and intra-laboratoryround-robin studies also assure the quality of the analyses.

No statistical analyses ofthe data were performed beyond occasional summary statistics.



### Results: Atrazine concentrations in the samples varied from non-detects (detection limit of0.001 Ilg/L) to 1.89 Ilg/L. (See Figure 2 and Table 4.) The atrazine concentrations atthe "background" sites (Sites 8 and 9) were consistently lowerthan those from Sites 5 and 10, but atrazine was often presentin the former, indicating the use ofatrazine elsewhere in the watershed. A small cornfieldupstream may have been contributing atrazine runoff; Site 9 (the less upstream background site) always hadhigher levels ofatrazine than Site 8 (the mostupstream site). Site 5, being closerto the tile plots, always had higher atrazine levels than Site 10.

Water chemistry data were interpreted as showing the dynamics ofseasonal groundwater contributions as well as changes in water quality due to tile plotrunoff. Groundwater contributions were inferred from observations ofapparentbase flow conditions at Site 5 during dry spells, as well as high specific conductance and concentration ofmajor ions (especially calcium and sulfate, indicating flow through the Mississippian gypsum shales common in the basin). See Table 3 for summary statistics ofwaterquality parameters for Sites 5, 8, 9, and 10 (no units were provided for any parameters, butbased on figure captions and text discussion, ion concentrations are probably mg/L and specific conductance is probably IlS/cm). Selectedparameters (calcium concentration, N03+N02 concentration, pH, dissolved organic carbon) are also graphed in Figure 3 through Figure 6. For most parameters except dissolved organic carbon, Site 5 had higherconcentrations than the other sites and the background sites had lower concentrations than Sites 5 or 10; concentrations ofpotassium andpH levels, however, were similar among these four sites. The authors interpret the results as indicating effects ofthe tile plotrunoffon the stream water quality, with additional effects due to varying relative flow contributions from groundwater.

The measurements ofthe plankton drift community found 103 species ofphytoplankton and 10 species ofzooplankton, including 76 diatoms, 18 green algae, 5 flagellates, and 5 bluegreen algae. Zooplankton were infrequent. A complete list ofphytoplankton species identified is tabulated in the original paper (Table 4), but is not reproducedhere. The most common phytoplankton species were: Cocconeisplacentula Cyclotella meneghiniana Fragilaria crotonensis F. virescens Aulacoseriagranulate Melosira varians Naviculapupula

3Pinnularia apendiculata P. borealis Surirella linearis S. ovulum S. tenera Synedra nana S. ulna Tabellariafenestra Tjlocculosa Spirogyra sp. Trachelomonas dybokskii 

### Phytoplankton cell counts and number ofspecies per sample (both net and water samples) are provided in Table 5, Table 6, and Table 7. The results show higherplankton numbers atthe background sites than in the sites affectedby tile plotrunoff. These planktonreductions in the field stream tendedto become less dramatic aftereach confluence and with distance downstream. Numbers ofspecies in each sample also varied dramatically, in time as well as by sample. (No statistical analyses provided.) Sce Figure 7 forthe variation ofphytoplankton cell counts overtime for Sites 5,8,9, and 10, and Figure 8 for the distributions ofdifferentplankton groups by time and site. Increases at Sites 10 and 11, as comparedto those ofthe background sites, are noted during September

- November 1989.
Microzoop1ankton were rare, and taxarepresented wereAmoeba, Braehinestapaludosa, Chaoborus, Colpoda, Daphnia, Limnoealanus, Nematode, Paramercium, and Tintinnid. From Septemberto November zooplankton were found at Sites 8 and 9 (150

- 14,630 cells/L) with fewer numbers at Sites 6 and 7 (570

- 933 cells/L), butoverall the distribution was "patchy".
Comparing Figure 2 with Figure 7, the authors state that changes in phytoplankton cell numbers are associatedwith atrazine concentrations, although they also note strong effects ofnitrates levels on the phytoplankton levels (higherphytoplankton levels with more nitrates). (No quantitative analyses or statistics are provided.)



### 4Figure 1. Diagram ofstudy location, including stream network (arrows indicate direction offlow) and sampling sites.



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Figure 2. Atrazine concentrations (/lglL) over time at the four sampling sites listed. Note vertical axis is log-scale.

Figure 3. Calcium concentrations (mg/L) over time at the four sampling sites listed.

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Figure 8. Distribution ofplankton groups over all sampling sites on each day ofsampling.

9Table 1. General descriptions ofsampling locations. (study table 1)

Site number Site description 1-4 Tile drainage outlets 5 Channel carrying tile f10w 6 Branch ofstream post-confluence 7 Branch ofstream post-conf1uence 8 Upstream background site 9 Upstream prior to confluence 10 Downstream aftermixing II Salt Spring Brook Stream depth (em)
15 15 10 30 30 20 100 Stream width (cm)

60 50 50 90 120 80 400

Precipitation (mm) Month Table 2. Monthly meteorological data from Havelock, New Brunswick station (approx. 10 km from site). (study table 2) Mean temp 

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Max. Min. June July August September October November 21.2 9.4 24.4 10.3 23.7 11.7 19.3 7.4 13.3 1.9

4 -3.9 64.8 99.8 114.7

88 48.4 153.8

10Table 3. Summary ofwaterquality data. No units are provided in the original. (study table 3)

Site 5 Site 8 Site 9 Site 10 Parameter Median Min. Max. Median Min. Max. Median Min. Ma."t. Median Min. Max. Color 12.5 5 80 10 5 30 10 5 40 10 5 30 Turbidity 1.7 0.6 32 0.7 0.4 28 0.4 0.3 30 0.7 0.3 25 Specificconductance 1190 375 1400 441 130 625 675 129 790 740 207 1100 pH 7.8 7.1 8 7.7 7.2 8.1 7.8 6.9 8.1 7.8 7.3 8 Total alkalinity 135 44.9 141 109 31 139 102 32 163 107 34 120 Calcium 200 46 271 58 15 87 86 16 108 112 26 160 Magnesium 29 10 34 12 3.5 15 16 3.3 18 18 5 23 Potassium 1.7 0.9 3.1 1.7 0.87 3.4 1.9 1 2.4 1.9 I 2.3 Sodium 39 10 49 13 4.3 23 20 5 37 27 6.9 40 Chloride 25 12 31 7.4 1.7 14 13 ND 16 16 3.9 23 Sulfate 546 210 758 98 18 220 200 20 266 280 44 440 Silica 27 9.8 30 12 8.6 15 13 7 15 16 1.4 20 Dissolvedorganic carbon 1.6 1.2 9.6 2.9 2.2 6.2 2.9 2.1 6 2.6 1.5 6.6 N03+N02 0.07 ND 3 0.11 ND 0.88 0.08 ND 0.9 0.08 ND 1.2 Total nitrogen 0.28 ND 4.4 0.36 0.13 1.4 0.3 0.13 1.6 0.27 0.15 2 Note: ND =notdetected

11Table 4. Atrazine concentration measurements in /-lg/L. "-" notation is not defined in the original. (from study table 5)

Collection Sampling site Date 1 2 3 4 5 6 7 8 9 10 /J 9-Jun-89 5.756 6.334 0.009 20.39 13.9 1.891 0.224 0.169 0.255 1.7 0.2 23-Jun-89 0.014 0.003 0.166 1.72 6.36 1.53 0.077 0.023 0.051 0.2 0.16 7-Jul-89 0.003 0.033 0.002 0.125 0.21 0.167 0.029 0.009 0.021 0.078 0.009 21-Jul-89 0.007 0.046 0.015 0.112 0.889 1.04 0.047 0.016 0.024 0.205 0.011 4-Aug-89 0.044 0.018 0.073 0.379 0.431 0.038 0.007 0.011 0.181 0.008 18-Aug-89 0.043 0.072 0.079 0.464 0.886 0.026 0.01 0.017 0.271 0.013 I-Sep-89 0.035 0.006 0.032 0.231 0.172 0.013 0.005 0.007 0.007 0.007 14-Sep-89 0.003 0.005 0.211 0.22 0.016 0.008 0.555 0.004 5-0ct-89 0.19 0.965 0.414 0.375 0.961 0.91 0.001 0.001 0.001 0.1 0.014 27-0ct-89 16-Nov-89

Table 5. Phytoplankton cell counts. "-" notation is not defined in the original. (from study table 5)
Collectio Samplingsite n 1 2 3 4 5 6 7 8 9 ]0 11 Date 9-Jun-89 1,79 1,06 650 9,980 14,040 33,44 78,200 90,060 7,560 2,710 0 0 0 23-Jun- 510 570 290 890 840 11,050 17,83 87,680 100,71 25,460 19,180 89 0 0 7-Jul-89 180 580 890 230 420 3,960 9,990 41,750 53,260 16,770 27,500 21-Jul-89 120 310 820 4,23 240 360 2,320 39,000 33,580 7,680 6,030 0 4-Aug-89 750 7,10 760 6,980 43,170 22,69 47,520 66,210 102,67 9,210 0 0 0 18-Aug- 150 2,56 2,31 820 13,26 4,460 62,200 24,700 20,630 14,170 89 0 0 0 I-Sep-89 2,26 790 9,770 12,030 42,75 88,910 123,09 152,98 51,060 0 0 0 0 14-Sep- 28 61,77 130,93 30,75 111,00 151,04 69,500 141,81 89 0 0 0 0 0 0 5-0ct-89 870 790 2,63 12,65 225,22 23,73 165,80 133,89 23,180 58,140 0 0 0 0 0 0 27-0ct- 290 790 52,88 64,610 85,51 90,050 116,90 46,280 31,630 89 0 0 0 16-Nov- 760 560 1,42 570 43,55 82,22 66,310 85,070 44,720 25,560 89 0 0 0

12Table 6. Number ofphytoplankton species in water samples. "- " notation is not defined in the original. (from study table 6)

Collection Samplingsite Date 1 2 3 4 5 6 7 8 9 10 11 9-Jun-89 3 2 3 9 8 8 10 12 7 3 23-Jun-89 2 2 1 1 2 6 5 13 13 4 5 7-Jul-89 1 2 4 1 1 4 3 10 14 4 3 21-Jul-89 2 2 3 2 3 1 3 11 8 4 4 4-Aug-89 2 4 1 4 7 5 8 10 10 5 18-Aug-89 2 2 1 5 3 8 8 4 4 I-Sep-89 2 1 4 4 9 10 10 8 9 14-Sep-89 6 7 5 8 9 9 10 5-0ct-89 2 3 2 13 7 12 9 4 8 27-0ct-89 1 1 8 11 11 12 15 13 13 16-Nov-89 1 2 4 1 16 12 10 12 12 11 11

Table 7. Numberofphytoplankton species in net samples. "- " notation is not defined in the original. (from study table 6)

Collection Samplingsite Date 1 2 3 4 5 6 7 8 9 10 11

9-Jun-89 5 2 3 6 10 10 13 17 18 8 10 23-Jun-89 4 ,., 1 3 4 14 9 19 21 8 9 -' 7-Jul-89 2 3 5 3 5 6 7 16 19 11 13 21-Jul-89 ,., 3 5 5 4 4 4 16 14 7 8 -' 4-Aug-89 7 7 10 7 14 11 17 14 14 12 18-Aug-89 4 5 6 ,., 11 9 7 19 17 9 13 .J I-Sep-89 3 6 3 8 7 15 14 17 9 15 14-Sep-89 2 3 12 15 14 19 14 15 19

5-0ct-89 4 3 1 4 10 16 14 19 14 14 14 27-0ct-89 2 2 1 2 13 12 16 16 22 28 22 16-Nov-89 1 3 6 4 19 19 14 20 19 17 16



### 13

### Data Summary Table: Effect Magnitude of Nominal Day of Time DidRecovery Comments Effect relative Atrazine StudyEffect Weighted Occur

- 

### If so, to controls Concentratio Occurred Average when (see
n (J.1g/L) Atrazine comment)? Concentratio
nfrom Day 0 to When Efject Occurred Comparison of

no (>166 Site 5 (nearDecline in not applicable 48 (day of days; partial field stream) phytoplankton >99% (4 Llhato tile maximum 5.3 Ilg/L to Site 8 (cell counts) plots) effect) recovery (background noted) site). See Table 5. Comparison of Decline in Site 5 (nearphytoplankton not applicable 34 (day of field stream) (number of 90% (4 Llha to tile maximum 6.I Ilg/L yes (Day 166) to Site 8 species)1 plots) effect) (background site). See Table 6.



### Time weighted averages were calculated from the atrazine concentration time series. Each datapointwas assumedto apply to the time interval starting atthe midpoint ofthe time period since the lastmeasurement, and ending atthe midpoint ofthe timeperiod until the next measurement. Time periods between measurements were all 14 days. The first datapoint coveredthe time period beginning at atrazine application, and the last data pointcovered only the previous 7 days. See below for calculations (linked to Excel spreadsheet).

I Ibid.



### 14Atrazine cones Date Site 5 Days coverage (Day-weight

9-Jun-89 13.9 10 139 23-Jun-89 6.36 14 89.04

7-Jul-89 0.21 14 2.94 21-Jul-89 0.889 7 6.223
TWA 21 July TWA 7 July 5.271178 6.078421



### Reviewer Comments: This study was a set ofobservations ofa single, natural stream during a single year. The object, apparently, was to evaluate effects on this stream ofknown atrazine additions on a systematic setup oftile plotwith known drainage. However, the plot-specific drainages (from Sites 1-4) were not analyzed, and insteadthe focus was on downstream sites where confounding was likely due to confluence with larger streams thatwere affected by dynamics elsewhere in the watershed. Background levels ofatrazine were well above the detection limit in the "control" locations, andthe authors discuss at lengththe issue of groundwater flow affecting water quality parameters (nutrient levels) that could in turn affectphytoplankton populations (the endpoint ofinterest). Moreover, the sampling design failed to observe baseline conditions priorto atrazine addition. Indeed, sampling didnotbegin until three days afterthe atrazine application, and in that intervening time there was a significant amount ofrainfall (16.6 mm). The most acute effects may therefore may have been missed due to the sampling approach.

In terms ofpresentation and data analysis, when citing numbers, the units associated with those quantities mustbeprovided in orderfor the datato be interpreted correctly, butin the water quality table as well as the description ofrainfall in the text, no units were provided. The methodology ofatrazine application, including the productused, was not discussed. Finally, there was no data analysis: near-raw datawere provided intables and graphs and then discussed in avisual or general way, butno statistics or analyses was done to quantify the assertions andprovide them with objective support. Forexample, the authors statethatthe phytoplankton time-series "appear[s] to coincide" with the atrazine time-series, butthe reviewer did notnecessarily agree aftervisually examining theplots and found thejudgment subjective.
Description ofUse 

### in Document (QUAL, QUAN, INV): INV

Rationale for Use: Study limitations describedbelow limitthe utility ofthe study. The systemtested was anatural system with drainage from agicultural areas. The presence of otherpesticides is likely to have occurred. Also, atrazine was detected in controls at levels that could influence the results.

15

### Limitations ofStudy: This was an uncontrolled, once-offfield experiment. Although the authors assert that their findings are evidence ofmild, transient downstream effects on phytoplankton communities, they provide no quantitative support for their conclusion, andthere are potentially significant confounders such as nitrate fluctuations and timevarying upwelling ofgroundwaterthrough a gypsum-rich substrate. Additionally, results are limited by the fact that sampling began three days after atrazine addition to the field plots, with no preliminary sampling to determine baseline conditions.


### Primary Reviewer: SaraHendrix, M.S., StaffScientist, Cambridge Environmental Inc

,1/ 

### SecondaryReviewer: Brian Anderson, U.S. EPA

# I'

16